Yoga Sutras of Patanjali · 3.11

सर्वार्थतैकाग्रतयोः क्षयोदयौ चित्तस्य समाधिपरिणामः॥११॥

sarvārthatā-ekāgratayoḥ kṣaya-udayau cittasya samādhi-pariṇāmaḥ

The transformation toward samadhi is the gradual decline of the mind's many-directedness and the rise of its one-pointedness.

— Yoga Sutras of Patanjali 3.11

Source: Sanskrit attributed to Patanjali (c. 2nd century BCE – 4th century CE). Public-domain English readings drawn from Swami Vivekananda's 'Raja Yoga' (1896) and Charles Johnston's 'The Yoga Sutras of Patanjali' (1912).